Dwindling petroleum reserves and deterioration in air quality caused by automotive emissions have resulted in massive efforts to improve the gasoline engine. The basic problem is that the internal combustion engine is inherently inefficient. Only a small fraction of the gasoline that it burns is actually converted into useful power. The remainder is dissipated in the form of heat or vibration, or consumed in overcoming friction between the engine's many moving parts. Some of the gasoline that enters the combustion chamber is not completely burned, and passes out the tailpipe as hydrocarbons (HC) or carbon monoxide (CO), two major components of air pollution or "smog". In view of the millions of automobiles and other gasoline-powered vehicles and engines operating in the world, it is evident that even a miniscule improvement in engine efficiency could result in substantial savings of petroleum and significant reductions in air pollution.
Combustion is an extremely complex reaction, especially under the conditions that exist in the cylinders of an internal combustion engine. However it is obvious that the efficiency of combustion will depend, at least in part, on the amount of oxygen that is present to support it. Various attempts have been made over the years to increase the amount of oxygen available to the combustion chamber. Devices such as turbochargers, superchargers, and auxiliary air injectors have been frequently employed to increase the air supply to the engine. Pure oxygen gas itself has been added to the air stream--for example, by Meeks, U.S. Pat. No. 3,877,450 or Gerry, U.S. Pat. No. 3,961,609. Devices for adding nitrous oxide, an oxygen substitute, to fuel-air mixtures have also been used.
Whereas these approaches have been at least partially successful, they require the installation of supplemental apparatus to the engine--e.g. a turbocharger, an oxygen tank and associated metering equipment, etc. It would be desirable to incorporate something directly into the fuel that would be capable of liberating supplemental oxygen in the combustion chamber. Such a chemical would be particularly useful if it could be simply added as needed to the gasoline tank by the consumer in the form of an aftermarket gasoline additive. Over the years, the derivatives of hydrogen peroxide have been studied as possible sources of supplemental oxygen for the fuel in the combustion chamber. For example, Hirschey, U.S. Pat. No. 4,045,188, discloses a gasoline additive comprising a mixture of di-tertiary buty peroxide with tertiary butyl alcohol as a stabilizer. Improvements in fuel economy were observed at the recommended treat levels. Some problems were observed, however. If the peroxide was used in excess of the recommended concentrations, the fuel economy actually deteriorated and there was a decrease, not an increase, in mileage. This sensitivity to concentration would present a problem to a consumer, inasmuch as it is not always easy to measure a precise amount of additive into a precise amount of gasoline in an ordinary gas tank. Moreover the presence of the tertiary butyl alcohol could also be a drawback, inasmuch as excessive amounts of alcohol in gasolines may have adverse effects on certain fuel system components and may also promote corrosion, water absorption, and other problems.
Earle, U.S. Pat. No. 4,298,351, discloses a fuel composition comprising methanol and from 7 to 25% of a tertiary alkyl peroxide. This composition is intended for use as a gasoline substitute--however it may also be employed in admixture with gasoline. Problems with autoignition and accompanying knocking in a conventional gasoline engine could be overcome by the addition of water and isopropanol. As with Hirschey, the use of alcohols, especially with added water, could present difficulties.
Harris and Peters in the journal Combustion Science and Technology, Vol. 29, pp. 293-298 (1982), describe the results of a study on mixtures of from 1 to 5% di-tertiary butyl peroxide in unleaded gasoline. A laboratory test engine was used, and improvements in the lean combustion of the fuel were observed. This reference, which teaches the utility of organic peroxide by itself, is considered to be close prior art.